Quick Answer
The correct inbound rule is TCP port 443 from source 0.0.0.0/0, because HTTPS traffic is transmitted over TCP port 443, and allowing all IPv4 addresses (0.0.0.0/0) permits any internet client to reach the web server securely. This rule ensures that only encrypted web traffic is accepted, while blocking unencrypted HTTP on port 80, administrative SSH on port 22, and RDP on port 3389. On the AWS Certified Security Specialty SCS-C02 exam, this concept tests your ability to distinguish common service ports and apply least-privilege security group rules for public-facing workloads. A frequent trap is confusing port 80 (HTTP) with port 443 (HTTPS), especially when the question explicitly states “only HTTPS.” Remember the mnemonic: “HTTPS is 443, HTTP is 80—secure always uses the higher port.”
This SCS-C02 practice question tests your understanding of infrastructure security. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A security engineer is configuring a security group for a web server that should only accept HTTPS traffic from the internet. Which inbound rule should be set?
TCP port 3389 from 0.0.0.0/0
Why wrong: Port 3389 is RDP.
TCP port 22 from 0.0.0.0/0
Why wrong: Port 22 is SSH.
TCP port 80 from 0.0.0.0/0
Why wrong: Port 80 is HTTP, not HTTPS.
TCP port 443 from 0.0.0.0/0
Port 443 is HTTPS.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
TCP port 443 from 0.0.0.0/0
Option B is correct because HTTPS uses TCP port 443. Option A is wrong because port 80 is HTTP. Option C is wrong because port 22 is SSH. Option D is wrong because port 3389 is RDP.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
TCP port 3389 from 0.0.0.0/0
Why it's wrong here
Port 3389 is RDP.
TCP port 22 from 0.0.0.0/0
Why it's wrong here
Port 22 is SSH.
TCP port 80 from 0.0.0.0/0
Why it's wrong here
Port 80 is HTTP, not HTTPS.
TCP port 443 from 0.0.0.0/0
Why this is correct
Port 443 is HTTPS.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
What to study next
Identify which SCS-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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FAQ
Infrastructure Security — This question tests Infrastructure Security — Read the scenario before looking for a memorised answer..
The correct answer is: TCP port 443 from 0.0.0.0/0 — Option B is correct because HTTPS uses TCP port 443. Option A is wrong because port 80 is HTTP. Option C is wrong because port 22 is SSH. Option D is wrong because port 3389 is RDP.
Identify which SCS-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 20, 2026
This SCS-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SCS-C02 exam.
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